At the largest terminal at New York’s John F. Kennedy International Airport on one of the busiest travel days of the year, security lapses enabled an unticketed passenger to board a plane to Paris in a shocking breach that one aviation expert said should serve as a “wake-up call” for the airline industry.

A woman who allegedly stowed away on a Delta Air Lines flight to Paris was filmed disrupting a return flight to New York after French officials denied her entry to the country.

It remains unclear how the person managed to bypass security at JFK Airport and board the Delta Airlines flight to Paris.